The present invention relates to an ink jet device comprising an ink reservoir for hot melt ink, a heater arranged to heat ink contained in the ink reservoir, and a ventilation conduit which is connected at a lower end thereof to a ventilation opening in a top wall of the ink reservoir, said ventilation conduit comprising a channel, the maximum diameter of which is smaller than the length of the channel. For example, the channel consists of a tube.
Ink jet printers operating with hot melt ink, i.e., with ink that is solid at room temperature, comprise an ink reservoir which can be heated in order to maintain the ink in the liquid state in which it can be supplied to the printhead. To prevent ink from leaking through a printing nozzle of the printhead, it has been proposed to apply a suction to a space of the ink reservoir through a ventilation conduit. For example, a negative pressure of approximately 1 kPa (10 mbar) is maintained within the space of the ink reservoir. However, when the ventilation opening of the ink reservoir is splattered with ink, ink may enter the ventilation conduit and may solidify inside the ventilation conduit, thus clogging the ventilation conduit. Under these conditions, the negative pressure can no longer be maintained in the space of the ink reservoir. The ventilation conduit might also be clogged in a similar manner if the ink reservoir is overfilled with melted ink.